Chevrolet Repair: heating&cooling, ac lines, freon

Question
1993chevy4x4pickup 350engine the ac lines freeze up and a very small amount of air comes out when I turn the heater/defrost on  

Answer
Hello Craig,
That can be one or both of two things.
Either a low charge of freon, or a real dirty evaporator core, restricting air flow.
If you don't spend tons of time on dusty dirty terrain, I would bet on the low freon. Get yourself a charge kit, and add a can of 134A.

Van